Backlash eliminating mechanism



Dec. 5, 1950 R. E. PRICE BACKLASH ELIMINATING MECHANISM Filed Dec. 8, 1948 jfh %neg Patented Dec. 5, 1950 EACKLASH ELIMINATING MECHANISM Ralph E. Price, Highfield, Md, assignor to Landis Tool Company, Waynesboro, Pa.

Application December 8, 1948, Serial No. 64,175

9 Claims.

This invention relates to a grinding machine, particularly a machine for grinding rolling mill rolls, and more particularly a machine of this type having a crowning mechanism for grinding rolls having convex or concave surfaces.

In grinding rolls having convex or concave surfaces, it is important that the traverse mechanism and the crowning mechanism be perfectly synchronized So that the relation between the grinding wheel and the surface being ground will remain the same regardless of the direction of traverse.

In the past, various types of mechanisms have been produced for compensating for backlash or for taking up backlash in a gear-driven apparatus. This invention represents an improvement on the previous backlash devices in that this device is power-operated and functions at each reversal of the traverse movement.

The drawing shows diagrammatically, essential elements in the traverse and crowning mechanisms. For further details of the crowning mechanism, reference is made to Patent No. 1,904,827, granted April 18, 1933. Details of the hydraulic motor for driving th traverse mechanism are disclosed in co-pending application 18,044, filed March 30, 1948. A Work carriage of the type to be operated by this traverse mechanism is disclosed in Patent No. 2,007,351, granted July 9, 1935.

Numeral Ill indicates a rack which is attached to the work carriage of the machine (not shown). Traverse movement of rack Ill is effected by means of a reversible hydraulic motor l5 through gear 15 on shaft ll. A train of gears consisting of a pinion 58 engaging the teeth of rack iii,

gears l9, 2?) and El transmits movement of said carriage to gear 22. Gear 22 is mounted on one end of shaft 23. At the other end of shaft 23 is a gear 25 engaging a gear 26 on shaft 2'! parallel to shaft 23. A helical gear 33 on shaft 2? engages a helical gear 31 on shaft 32, which extends transversely of shaft 2?. Shaft 32 drives a crowning mechanism 35.

On the opposite end of shaft 2i from gear 26 is a piston id, slidably mounted in cylinder M. The extent of movement of said piston is determined by an adjustable stop 52 in the head end of cylinder ll.

Fluid under pressure from pump 59 is supplied through line 55 to reversing valve 52. Said reversing valve directs fluid through lines 53 and 54 and lines 55 and 55A and 56 and 56A to corresponding sides of motor 55 and cylinder 4!.

stroke of piston 41!.

Operation With reversing valve 52 in the position shown, fluid under pressure is directed through lines 53 and 55 to drive motor I5 in a clockwise direction. At the same time, fluid under pressure is directed through line'55A to the head end of cylinder 45. Piston moves shaft 21 and helical gear 36 axially toward the right. The teeth on gears 30 and 3! co-act as cam surfaces so that gear 39 will begin to rotate until all backlash in the gearing between gear 26 and rack Ill has been taken up. Piston 4!! will then have reached the end of its stroke. At this point the crowning mechanism and the rack in will begin to move simultaneously.

When reversing valve 52 is shifted to direct fluid through lines 54, and 58A to the opposite side of motor l5 and cylinder 3!, 'the abovedescribed action is repeated in the reverse direction.

For most roll grinding jobs it is desirable that the crowning mechanism and the traverse mechanism be in perfect synchronism. However, in some cases it is necessary that these mechanisms be out of synchronism but by a predetermined amount. This has been accomplished by using the adjusting screw 52 to change the length of By proper adjustment of the stroke of piston All, it is possible to remove all or a predetermined part of the backlash in the traverse mechanism. It is even possible to effect this adjustment to a position beyond that at which all the backlash is taken up.

Iclaim:

1. In a grinding machine, a traverse mechanism, a hydraulic motor for driving said traverse mechanism, a crowning mechanism, gearing connecting said traverse mechanism and said crowning mechanism including transverse shafts, one

' of which drives said second mechanism; a helical gear on each of said shafts and means for starting said traverse mechanism and said second mechanism simultaneously after each reversal thereof, which consists in means for effecting axial movement of one of said helical gears in a direction corresponding to the direction of said traverse movement.

2. In a grinding machine, a traverse mechanism, a hydraulic motor for driving said traverse mechanism, a crowning mechanism, gearing connecting said traverse mechanism and said crowning mechanism including transverse shafts, one of which drives said second mechanism, a helical gear on each of said shafts, means for starting said traverse mechanism and said second mechanism simultaneously after each reversal thereof, which consists in means for effecting axial movement of one of said helical gears in a direction corresponding to the direction of said traverse movement, and means for adjusting the extent of said axial movement.

3. In a grinding machine, a traverse mechanism, a reversibie hydraulic motor for driving said traverse mechanism, a crowning mechanism, gearing connecting said traverse mechanism and said crowning mechanism and a backlash reversible mechanism in said gearing for taking up the backlash between said mechanisms at each reversal of said traverse mechanism in a direction corresponding to the direction of movement of said traverse mechanism.

4. In a grinding machine, a, traverse. mach anism, a reversible hydraulic motor for driving said traverse mechanism, a crowning mechanism, gearing connecting said traverse mechanism and said crowning. mechanism and a backlash mechanism in said gearing for taking .up the backlash between said mechanisms, and reersible power means for actuating said backlash mechanism automatically at' each. reversal of said traverse mechanism in a direction corresponding to the direction of movement of said traverse mechanism.

5. In a grinding machine, a traverse mechanism, a hydraulic motor for driving said traverse mechanism, a crowning mechanism, gearing connecting said traverse mechanism and said crowning mechanismincluding transverse shafts, one of whichdrives said second mechanism, a helical gear on each of said shafts and means, for starting said traversev mechanism and, said second mechanism simultaneously after each reversal thereof, which consistsin efiecting axialmovement of one of said helical gears in a direction corresponding to the direction of said traversev movement.

6. In a grinding machine, a traverse mechanism, a. reversible hydraulic motor for driving sai traverse mechanism, a crowning mechanism, gearing connecting said. traverse mechanism and said crowning mechanism and a backlash mechanism in said gearing for taking up the backlash between said-inechanisms, and reversible means foractuating said backlash mechanism automatically at. each reversal of said traverse mechshaft, means on said second shaft to resist rotation thereof, a helical gear on said second shaft meshing with said helical gear on said first shaft, means for effecting endwise movement of said first shaft, the helical gear on said first shaft turning slightly due to the cam action between said gears resulting from said endwise movement whereby to take up backlash in said gearing and thus permitting initiationof rotation of said second helical gear and movement of said rack atth same time.

8. In a grinding machine, a traverse mechanism, a second mechanism operable in timed relation with said traverse mechanism, a motor for driving said traverse mechanism, connections between said traverse mechanism and said second mechanism including a pair of shafts, one of which is driven from the traverse mechanism, meshing: gears in said shafts whereby said one shaft drives the other, said other shaft having a helical gear thereon engaging a second helical gear on saidsecond mechanism, means for shift.- ing said other shaft axially at each reversalof saidtraverse mechanism, said axial movement being effective to cause a slight turning of the helical gear thereonsuflicient to take up all backlash between said traverse mechanism and said secondv mechanism, and means to adjust the extent of axial movement of said other shaft to conform to the amount of backlash in said first mechanism.

9. In a grinding machine, a traverse mechanism, a hydraulic motor for driving said traverse mechanism, a crowning mechanism, gearing connecting said traverse mechanism and said crowning mechanism including transverse shaftaone of which drives said crowning mechanism, a helical gear oneach of said shafts, means for starting said traverse.- mechanism and said crowning Imechanism in predetermined relation after each reversal thereof, which includes means for effecting axial movement of one of said helical gears in a direction corresponding to thev directtion of said traverse movement, and means for adjusting the extent of said axial movement whereby to effecta predetermined adjustment in angular relation between said crown-ing mechanism and said traverse mechanism.

RALPH E. PRICE.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,254,010 Herfurth et al Aug. 26, 1941 2,254,784 Silven Sept. 2, 1941 

